A landing gear door retraction device

Abstract

A landing gear door retraction device is disclosed, which can be used to open and close the landing gear door of a reusable aircraft. It is characterized by comprising: a door actuator and multiple sets of linkage mechanisms. The device uses an independent door actuator to drive multiple sets of four-bar linkages, making it suitable for aircraft with high flight speeds, limited cabin space, and multi-leaf landing gear doors. It offers significant advantages such as light weight, small size, simple timing, and good synchronization. When the landing gear door is fully open, all three sets of four-bar linkages are near their dead center positions, preventing damage to the door structure caused by actuator overtravel. The door retraction device is located near the side and top walls of the landing gear bay, requiring minimal space and fully utilizing the remaining cabin space after the landing gear is retracted.

Description

Technical Field

[0001] This invention relates to a landing gear door retraction device, belonging to the field of reusable aircraft technology. Background Technology

[0002] Landing gear doors on aircraft are used to maintain the aircraft's aerodynamic shape when closed and to create structural passageways for landing gear deployment and retraction when open. Landing gear doors are typically single or multi-leaf, with multiple doors of different sizes used depending on the size of the landing gear deployment / retraction envelope. This minimizes the door area while still meeting the requirements for landing gear deployment / retraction passageways, reducing the impact on the fuselage structural integrity and the aerodynamic loads during door opening / closing, thereby reducing the pressure and power requirements for deployment and retraction.

[0003] Door retraction and extension mechanisms are generally divided into two types: independent mechanisms and linked mechanisms. Independent mechanisms use door retraction and extension actuators to control door opening and closing, independent of landing gear retraction and extension. Linked mechanisms select a drive point on the landing gear moving parts, such as landing gear struts or drag struts, and drive the door opening and closing via a linkage mechanism. Linked mechanisms transfer aerodynamic loads from the door to the landing gear during opening and closing, which can severely hinder landing gear lowering and even prevent the landing gear from lowering under its own weight, thus losing a lowering redundancy function. For high-speed aircraft, independent mechanisms are typically used to drive door opening and closing. For independent mechanisms driving multiple doors, equipping each door with an independent actuator introduces problems such as large size and weight, high energy requirements for retraction and extension, complex timing, and difficulty in ensuring synchronization. Therefore, it is necessary to design an independent mechanism to drive the synchronous opening and closing of multiple doors. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an aircraft landing gear door retraction and extension device that can save landing gear bay space, is lightweight, has simple timing, and good synchronization.

[0005] The technical solution of the present invention is: a landing gear door retraction device, suitable for connection to the door and the fuselage structure, driving the landing gear door to move back and forth between the open position and the closed position. The retraction device includes a door actuator, crank I, crank II, connecting rod I, connecting rod II, connecting rod III, pull rod, door I, door II, door III, and door hinge arm.

[0006] One end of the hatch actuator is connected to the fuselage structure, and the other end is connected to the lug I on the crank I of the hatch retraction device, providing driving force for the entire hatch retraction device;

[0007] Crank I is mounted on the engine body structure. Lugs I, II, III, and IV on crank I are connected to the door actuator, connecting rod I, connecting rod II, and pull rod, respectively.

[0008] Crank II is mounted on the machine body structure. Lugs V and VI on crank II are connected to connecting rod III and tie rod.

[0009] Doors I, II, and III are connected to the fuselage structure via door hinge arms. Doors I and II are arranged front to back and rotate around the same axis, which is located on one side of the landing gear bay. Door III rotates around an axis located on the other side of the landing gear bay. Doors I and III are arranged side to side and, when opened, provide a retraction and extension passage for the landing gear wheels and tires. The sum of their widths is wider than the width of the retraction and extension passage for the wheels and tires. When opened, Door II provides a retraction and extension passage for the landing gear struts and support rods. Its width is wider than the width of the retraction and extension passage for the landing gear struts and support rods, but smaller than the sum of the widths of Doors I and III.

[0010] One end of the connecting rod I is hinged to the lug II on the crank I, and the other end is hinged to the hatch I. The lug II on the crank I, the connecting rod I, and the hatch I hatch hinge arm constitute a four-bar linkage I, which transmits the driving force of the hatch actuator to the hatch I.

[0011] One end of the connecting rod II is hinged to the lug III on the crank I, and the other end is hinged to the hatch II. The lug III on the crank I, the connecting rod II, and the hatch II hatch hinge arm constitute a four-bar linkage II, which transmits the driving force of the hatch actuator to the hatch II.

[0012] One end of the lever is hinged to the lug IV on crank I, and the other end is hinged to the lug VI on crank II. The lug IV of crank I, the lever, and the lug VI of crank II constitute a four-bar linkage III, which transmits the driving force of the hatch actuator to crank II through crank I.

[0013] One end of connecting rod III is hinged to lug V on crank II, and the other end is hinged to hatch III. Crank II lug V, connecting rod III, and hatch III hatch hinge arm form a four-bar linkage IV, which transmits the driving force of the hatch actuator to hatch III.

[0014] When the door actuator retracts, it drives crank I to rotate counterclockwise, which in turn drives four-bar linkages I and II to rotate door I and II downwards around their pivot axis, opening door I and II. The counterclockwise rotation of crank I drives four-bar linkage III to rotate crank II counterclockwise, which in turn drives four-bar linkage IV to rotate door III downwards around its pivot axis, opening door III. When the door actuator retracts to a certain position, four-bar linkages I, II, III, and IV simultaneously move to near their dead center positions, at which point the landing gear door is fully open. As the door actuator continues to retract, the landing gear door will not continue to open, preventing damage to the landing gear door due to overtravel failure of the door actuator. The closing process of the landing gear door is the reverse of the opening process.

[0015] The advantages of this invention compared to the prior art are:

[0016] This invention provides a landing gear bay door system with three doors of different sizes, divided according to the landing gear retraction / extension envelope, minimizing the door area while meeting the landing gear retraction / extension passage requirements. All door retraction / extension devices are located inside the landing gear bay, arranged near the side and top walls, fully utilizing the remaining bay space after landing gear retraction. The door retraction / extension devices will not interfere with the retracted landing gear in any state. When the doors are fully open, the landing gear bay doors and door retraction / extension devices will not interfere with the landing gear during retraction / extension. The driving force of the door actuator is simultaneously transmitted to door I, door II, and door III, controlling the opening and closing of all three doors simultaneously, resulting in good door movement synchronization. The opening process of the three doors only requires controlling one door actuator, simplifying the timing relationship with the landing gear retraction / extension actuator. Attached Figure Description

[0017] Figure 1 This is a perspective view of an aircraft landing gear door retraction device according to a specific embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the installation of the landing gear door retraction device for an aircraft;

[0019] Figure 3 This is a schematic diagram of crank I;

[0020] Figure 4 This is a schematic diagram of crank II;

[0021] Figure 5 This is a schematic diagram of the motion principle of a four-bar linkage.

[0022] Figure 6 This is a schematic diagram showing the landing gear in its retracted position.

[0023] Figure 7 This is a diagram showing the landing gear in the middle position;

[0024] Figure 8 This is a diagram showing the landing gear in the lowered position. Detailed Implementation

[0025] The implementation and use of specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] The present invention provides a landing gear door retraction device for connecting to a door 80 and an airframe structure 200, driving the landing gear door 80 to reciprocate between an open position and a closed position; comprising: a door actuator 10, crank I20, crank II30, connecting rod I40, connecting rod II50, connecting rod III60, a pull rod 70, a door I81, a door II82, a door III83, and a door hinge arm 84;

[0027] The hatch actuator 10 is used to provide driving force for the entire hatch retraction and extension device 100. One end of the hatch actuator 10 is connected to the fuselage structure 200, and the other end is connected to one end of the crank 120.

[0028] Crank I20 is mounted on the fuselage structure 200. One end is connected to the door actuator 10, and the other three ends are connected to the connecting rod I40, connecting rod II50, and pull rod 70, respectively.

[0029] Crank II 30 is mounted on the machine body structure 200, with one end connected to the tie rod 70 and the other end connected to the connecting rod III 60;

[0030] Connecting rod I40 is connected at one end to crank I20 and at the other end to hatch I81;

[0031] Connecting rod II50, one end is connected to crank I20, and the other end is hinged to hatch II82;

[0032] Connecting rod III60 is connected at one end to crank II30 and at the other end to hatch III83;

[0033] The pull rod 70 is connected at one end to crank I20 and at the other end to crank II30;

[0034] Doors I81, II82, and III83 are respectively mounted on the fuselage structure 200 via door hinge arms 84;

[0035] Doors I81 and II82 are arranged fore and aft along the direction of the aircraft's flight and rotate around the same pivot, which is located on the outer wall of the landing gear bay.

[0036] Door III83 rotates around a pivot located on the inner side wall of the landing gear bay; Door I81 and Door III83 are arranged in a split configuration, which, when opened, creates a retraction and extension passage for the landing gear wheels and tires 302; Door II82, when opened, creates a retraction and extension passage for the landing gear struts 301 and support rods.

[0037] The width of hatch II82 is greater than the width of the landing gear strut 301 and the extension and retraction passage of the strut, and the width of hatch II82 is less than the sum of the widths of hatch I81 and hatch III83.

[0038] The combined width of hatch I81 and hatch III83 is greater than the width of the landing gear and tire 302 retraction and extension passage.

[0039] The width of hatch II82 is wider than the width of landing gear strut 301 and the strut retraction and extension passage, but less than the sum of the widths of hatch I81 and hatch III83.

[0040] The crank I20 is an integrally molded structure, including lugs I21, II22, III23, IV24 and bushing I25; lugs I21 and IV24 are arranged in the same normal plane in the middle of bushing I25, and lugs II22 and III23 are symmetrically arranged at both ends of bushing I25; lugs I21, II22, III23 and IV24 are respectively connected to the door actuator 10, connecting rod I40, connecting rod II50 and pull rod 70.

[0041] The crank II30 is an integrally molded structure, including lugs V31, VI32 and bushing II33; lugs V31 and VI32 are respectively arranged at both ends of bushing II33; lugs V31 and VI32 are respectively connected to connecting rod III60 and pull rod 70.

[0042] The lug II22, the connecting rod I40 and the door hinge arm 84 constitute a four-bar linkage I91, which is used to transmit the driving force of the door actuator 10 to the door I81.

[0043] The lugs III23, the connecting rod II50, and the door hinge arm 84 constitute a four-bar linkage II92, which is used to transmit the driving force of the door actuator 10 to the door II82.

[0044] The lug V31, the connecting rod III60 and the door hinge arm 84 constitute a four-bar linkage IV94, which is used to transmit the driving force of the door actuator 10 to the door III83.

[0045] The lug IV24, the pull rod 70, and the lug VI32 constitute a four-bar linkage III93, which is used to transmit the driving force of the hatch actuator 10 to the crank I20 through the crank II30.

[0046] When the door actuator 10 retracts, it drives the crank I20 to rotate counterclockwise. On one hand, this drives the doors I81 and II82 to rotate around the pivot axis via the four-bar linkages I91 and II92, thus opening the doors I81 and II82. On the other hand, it drives the crank II30 to rotate counterclockwise via the four-bar linkage III93, which in turn drives the door III83 to rotate around the pivot axis via the four-bar linkage IV94, thus opening the door III83. When the door actuator 10 retracts to the designated position, the four-bar linkages I91, II92, III93, and IV94 simultaneously move to the dead position. At this time, the landing gear door 80 is fully open. When the door actuator 10 continues to retract, the landing gear door 80 will not continue to open, thus avoiding damage to the landing gear door 80 due to overtravel failure of the door actuator 10. The closing process of the landing gear door 80 is the reverse of the retraction process.

[0047] The retraction and extension device of this embodiment has the following characteristics: the landing gear bay door 80 is divided into multiple panels to minimize the area of ​​the door 80 while meeting the retraction and extension passage requirements of the landing gear 300; all door retraction and extension devices 100 are located inside the landing gear bay, making full use of the remaining bay space after the landing gear 300 is retracted; the door retraction and extension devices 100 will not interfere with the retracted landing gear 300 in any state; when the door 80 is fully open, the landing gear bay door 80 and the door retraction and extension devices 100 will not interfere with the landing gear during the retraction and extension process; the driving force of the door actuator 10 is simultaneously transmitted to the door I 81, door II 82, and door III 83, simultaneously controlling the opening and closing of the three doors 80, resulting in good door movement synchronization; the opening process of the three doors 80 only requires control of one door actuator 10, simplifying the timing relationship with the retraction and extension of the landing gear 300.

[0048] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A landing gear door retraction device for attachment to a door and a body structure to drive the landing gear door to and from an open position and a closed position; characterised in that, include: Door actuator, crank I, crank II, connecting rod I, connecting rod II, connecting rod III, pull rod, door I, door II, door III, door hinge arm; The hatch actuator is used to provide driving force for the entire hatch retraction and extension device. One end of the hatch actuator is connected to the fuselage structure, and the other end is connected to one end of crank I. Crank I is mounted on the fuselage structure, with one end connected to the door actuator and the other three ends connected to connecting rod I, connecting rod II, and pull rod, respectively. Crank II is mounted on the machine body structure, with one end connected to the tie rod and the other end connected to the connecting rod III; Connecting rod I, one end is connected to crank I, and the other end is hinged to hatch I; Connecting rod II is connected to crank I at one end and hinged to hatch II at the other end; Connecting rod III is connected to crank II at one end and hinged to hatch III at the other end. The pull rod is connected at one end to crank I and at the other end to crank II. Door I, Door II, and Door III are respectively mounted on the fuselage structure via door hinge arms; Door I and Door II are arranged front and rear along the direction of the aircraft's flight and rotate around the same axis, which is located on the outer wall of the landing gear bay. Door III rotates around a pivot located on the inner side wall of the landing gear bay; Door I and Door III are arranged in a split configuration, which, when opened, provides a retraction and extension path for the landing gear wheels and tires; Door II, when opened, provides a retraction and extension path for the landing gear struts and braces.

2. A landing gear door retraction apparatus according to claim 1, wherein, The width of hatch II is greater than the width of the landing gear strut and support rod retraction passage, and the width of hatch II is less than the sum of the widths of hatch I and hatch III.

3. A landing gear door retraction apparatus according to claim 1, wherein, The combined width of hatch I and hatch III is greater than the width of the landing gear and tire retraction passage.

4. The landing gear door retraction device according to claim 1, characterized in that, The crank I is an integrally molded structure, including lug I, lug II, lug III, lug IV and bushing I; lug I and lug IV are arranged in the same normal plane in the middle of bushing I, and lug II and lug III are symmetrically arranged at both ends of bushing I; lug I, lug II, lug III and lug IV are respectively connected to the door actuator, connecting rod I, connecting rod II and tie rod.

5. A landing gear door retraction device according to claim 4, characterized in that, The crank II is an integrally molded structure, including lug V, lug VI and bushing II; lug V and lug VI are respectively arranged at both ends of bushing II; lug V and lug VI are respectively connected to connecting rod III and tie rod.

6. A landing gear door retraction device according to claim 5, characterized in that, The lug II, the connecting rod I, and the door hinge arm constitute a four-bar linkage I, which is used to transmit the driving force of the door actuator to the door I. The lug III, the connecting rod II, and the hatch hinge arm constitute a four-bar linkage II, which is used to transmit the driving force of the hatch actuator to the hatch II. The lug V, the connecting rod III, and the door hinge arm constitute a four-bar linkage IV, which is used to transmit the driving force of the door actuator to the door III. The lugs IV, the pull rod, and the lugs VI constitute a four-bar linkage III, which is used to transmit the driving force of the hatch actuator to the crank I through the crank II.

7. A landing gear door retraction device according to claim 6, characterized in that, When the door actuator retracts, it drives crank I to rotate counterclockwise. On one hand, this drives four-bar linkages I and II to rotate door I and door II around their axis, thus opening door I and door II. On the other hand, it drives four-bar linkage III to rotate crank II counterclockwise, which in turn drives four-bar linkage IV to rotate door III around its axis, thus opening door III. When the door actuator retracts to the designated position, four-bar linkages I, II, III, and IV simultaneously move to their dead center positions. At this point, the landing gear door is fully open. When the door actuator continues to retract, the landing gear door will not continue to open, thus preventing damage to the landing gear door due to overtravel failure of the door actuator. The closing process of the landing gear door is the reverse of the opening process.

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